Hydrophobic solvation increases thermal conductivity of water. Issue 37 (18th September 2020)

• Record Type: Journal Article
• Authors: López-Bueno, Carlos; Suárez-Rodríguez, Manuel; Amigo, Alfredo; Rivadulla, Francisco
• Is Part Of: Physical chemistry chemical physics. Volume 22:Issue 37(2020)
• Page Start: 21094
• Page End: 21098
• Publication Date: 2020-09-18
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d0cp03778h
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The rearrangement of the H-bond network in bulk water induced by a small concentration of ethanol is not only reflected in the frequency of the libration band of water, but also in a surprising increase of its thermal conductivity. Abstract : The interaction of water with small alcohols can be used as a model for understanding hydrophobic solvation of larger and more complex amphiphilic molecules. Despite its apparent simplicity, water/ethanol mixtures show important anomalies in several of their properties, like specific heat or partial molar volume, whose precise origin are still a matter of debate. Here we report high-resolution thermal conductivity, compressibility, and IR-spectroscopy data for water/ethanol solutions showing three distinct regions of solvation, related to changes in the H-bond network. Notably, the thermal conductivity shows a surprising increase of ≈3.1% with respect to pure water at dilute concentrations of ethanol ( x = 0.025), which suggests a strengthening of H-bond network of water. Our results prove that the rate of energy transfer in water can be increased by hydrophobic solvation, due to the cooperative nature of the H-bond network.